Research suggests that psychological trauma may produce sensitization of the amygdala and related regions simultaneously with desensitization of the hypothalamus-pituitary axis (HPA) system of the PNS. There are no studies to date that simultaneously examine the central and peripheral effects of trauma, and none that compare the long-term effects of trauma on the amygdala in children relative to adults. The proposed study compares a non-clinical sample of children (n=24) and adults (n=24) who were within a mile of the World Trade Center (WTC) on 9/11/01 to matched control groups who lived at least 300 miles away from the New York City or Washington, D.C. areas between 9/11/01 and 9/11/02. FMRI will be used to measure amygdala activation; subjects will view blocks of fearful and neutral faces, a paradigm that has been used previously to study amygdala function in children and adults. The peripheral stress response will be measured through salivary cortisol production, assessed as diurnal change and as acute change due to the fMRI process itself. It is hypothesized that children and adults who have been exposed to trauma will show hyperactivity in the CRF system (amygdala activity) and hypoactivity in the HPA system (cortisol response). [unreadable] [unreadable]